<?php
function uuid($prefix = '')

{

	$chars = md5(uniqid(mt_rand(), true));

	$uuid  = substr($chars,0,8) . '-';

	$uuid .= substr($chars,8,4) . '-';

	$uuid .= substr($chars,12,4) . '-';

	$uuid .= substr($chars,16,4) . '-';

	$uuid .= substr($chars,20,12);

	return $prefix . $uuid;

}